Radio tuning apparatus



R. C. ENDERWOOD RAQIO TUNING APPARATUS Dec. '1 1931.

Filed March 25, 1929 2 Sheets-Sheet 1 INVENTOR RICHARD C. ENDERWOOD BY MW g;

I ATTORNEY Dec. 1, 1931.

R. C. ENDERWOOD,

RADIO TUNING APPARATUS Filed March 25, 1929 2 Sheets-Sheet '2 5 A INVENTOR I RICH/42D c. ENDEEWOOD B Y m/III:

ATTORNEY i quencies.

Patented Dec. 1, 1931 UNITED {STATES PATENT. OFFICE RICHARD C. ENDERdFOOD, OF NEWARK, NEW JERSEY, ASSIGNOR TO BRANDES LABORA- TORIES, INCORPORATE), OF NEWARK, NEW JERSEY, A CORPORATION OF JERSEY mm mute arrmarus Application filed March 25, 1929. Serial No'. '349;707.-

This invention relates to means for adj usting or tuning radio receiving apparatus and particularly to means for automatically selecting certain definite radio broadcast fre An object of the invention is to simplify the tuning of radio receivers and to facilitate the locating of any desired broadcast wave lengths.

-Another object of the invention is to provide a tuning system which may be operated as efiiciently and effectively by a non-skilled operator as by one familiar with the method of locating broadcastingstations.

A further object of the invention is to'provide a method of'and means for tuning radio receiving sets which reduces the time required for tuning in any station over that which has heretofore been necessary with the usual type of radio. receiver tuning apparatus.

A feature of the invention is that it is adaptable to any of the well known types of radio'receiving systems.

Another feature of the invention is that it is a simple unitary control capable of manufacture at a small cost.

-To accomplish the foregoing objects, the tuning mechanism is substantially in the form of the well known radio receiver dial,'with.

the advantage of enabling the operator'to locating a station wave length qui accurately, a saving in operating pow accomplished since the power necessary for any desired volume may be reduced to a minimum forthe particular station being received. tion at the samevolume level when not tuned in at the most eflicient point of adjustment, at the expense of an increased power input. 3 In the present invention this minimum power input may be determined readily and accurately to prevent the receiving set being operated in an ineflicient manner.

select a radio ljr'oadcast wave length in asingle positive movement of the dial or conprevents the rcep ion'of asta-.

Other features and advantages of the;in-' .vention will be apparent and more fully understood by reference to the accompanying drawings in which: v

Fig. 1 is a front elevational view of a articular type of dial embodying the invention;

Fig. 2 is a cross sectional view of the dial of F ig. 1;

Fig. 3 is a modification of the locking arrangement of the dial shown in. Figs. 1 and 2;

' Fig. 4 is a cross sectional view of a portion of the locking stop shown in Fig. 3;

Fig. 5 is a front elevational view of a modification of the 'dialand stop'arrange: ment with parts broken away; and

Fig. 6 is a cross sectional View of the modification of Fig. 5.

Referring to Figs. 1, 2, 3 and 4 in detail wherein corresponding. numerals refer to similar elements .of the invention, an es cutcheon plate 5 is shown mounted on any well knowntype of radio receiver panel -6. A main operating arm 7 is fixedly and directly attached to rotatable shaft 8 which carries a variable tuning condenser 9 sup-,

ported on a frame12. The main control arm and condenser-are shown mounted on the same shaft but it is to be understood that any well known drive may be employed such as a belt and pulley combination, a gear train or a friction drive. 1 Also, the condenser 9 is representative-of a' gang condenser unit so ough he condenser 9 is'to be generaL ntifolled by-the arm 7, it ,may be add through the disc 10 inany suitable manner such as by a Vernier friction wheel 14'mounted on a rotatable shaft 15manual ly operated by an adjustin knob 16. The condenser 9 may now be a justed'and 'controlled by either the knob 16 through the friction wheel train 14 and. 10 or directly through the operatin arm 7Iby means of a main adjusting kim 20. However, when the txming'apparatushas been once adjusted, tuning in accordance with the invention as shown in Figs. 1,2,3 and 4: beaccom- 100 plished by means of the knob 20 the friction having a carrier frequency very near tion wheel 14 offering substantially no deleterious braking effect on the disc 10.

The knob 20 is mounted on a threaded screw 21 ermitting the knob to be tightened against t e arm 7. When the knob 20 is not so tightened it and the screw 21 may be moved radially; along the arm Tin ,a" slot 22 carrying therewith tapered pin 23 which is held: extended bye spring 24 a radial slot within the arm 7.

The .pin 23 is adapted to engage a plurality of stops or tabs having recesses 29 therein, the stops being placed in a circumferential path 31 in the escutcl'reon plate "5. The stops are adjustable along the path 31 but miiy be fixedly attached to the escutcheon plate at required points an suitable means such as setscrews 32. ese stops may -be placed at points along the path 31 which, when the pin 23 isinserted in one of the recesses 29, the condenser 9 will be in a. position'to permit the reception of a articular station. "The stops 30 maybe designated'by indicator cards 35 inserted in recesses in the faces of the stops.

When these" stops have been adjusted-so that, when the control arm is engaged therewith, certain stations will be received, these stations may be tuned in by thesingle 21peration of moving the operating arm 7 to e tab designating the particular station desired and allowing the spring 24 to insert the pin 23 in the receiving recess of the respective'ta'bs.

When it is desired to locate a new station,

for which the location of a tab has not been predetermined, the knob 20 ma be moved radially toward the shaft 8. unti the pin '23 is clear of the recess 29 and then tightened against the arm 7. "The shaft '8 may now rotat/e freely under the control of the vernier knob 16, or, in case rapid manipulation is desired, under control of the arm 7.

Any number of stops up to the capacity of path 31 may be employed, the stops being of any suitable shape although preferably of a' 'liey'st'one or a wedged shape pattern as shown'to rmit of a greater number being utilized within the confines of the path pro- "vided. It may also be desirable to have a reduction drive of two to one between the arm 7 and condenser 9 permitting the arm 7 to rotate 360 degrees to the 180 degree angular travel of the condenser. With this ar- 'rangement, a greater number of stops may hei e be'used, the path 31 now forming a complete circle. ,This arrangement will permit the use 'of s'tqpsIfor stations having carrier. frequencies located near each other.

" It within the contemplation of this invention that with a particularly selective receiver, two or more control arms similar tomrm 7 m 7 be extended from the control lathe logging of adistant stathat of a previously logged local station. To accomplish this control, an auxiliary arm may engage a stop on an unused portion of the path 31, which will move the originally locked arm less than the width of a stop.

Although an' method may be used toposition a stopv or a particular station, it is v preferable to proceed by locking pin 23 in a release osition, adjusting tuning. element 9 to its exact position -by-.means of yernier knob 16, moving a stop to an engaging powith arm 7, and then fastening the of tabs 30 are placed in their faces and a threaded pin 40 is. adapted to be inserted therein under control of a knob 41. The pin 40 is .held in any articular recess by means of a s ring 42. I '0 remove the pin and release t e operating arm 7, it is only necessary to pull the knob 41 toward the operator. The shaft 8 may now be rotated to another stop or: to any other position desired. A

slight turn ofthe knob 41 removes the pin 40 from the tab 30 and looks it in the release position to enable the condenser to be operated by means of th e vernier ltn'ob'lfi.

In Fi 5 and .6 adjustmentoffa shaft '50 is contr friction wheels 53 and 54am! :1, "ction disc 55, the disc bein mounted on theshaft 50. The disc 55 has t ereon a scale58 indicatin wave lengths or frequencies within the broa casting range which may be viewed through an aperture .59 in an escutcheon plate 60 mounted on a panel 61, The friction wheel 54 is for the purpose of imparting'to the disc 55 the same direction of rotation, as that of the control knob 51.

In this embodiment of the invention a control arm '64 mounted on shaft 50 has located therein a flat notched 65 which is held extended by a coil spri-n 66. The

tached to the arm '64 and co ed within the limits of a slot 68 in thefpin 65. The arm" in is limited in 1ts travel by a e 67 fi'xe y atlagare limited in their motion, when once located, by the dimensions of slots 75 working against a key 72. Snap keys 73 hold the buttons in position. Station indicating cards 74 are snapped in the faces of the buttons 70. A method of locating these buttons at positions in the path 69 corresponding to tuning points of the stations frequently desired is substantially the same as the method employed in locating the stops 30 of the system shown in Fig. 1.

To operate the tuning system shown in Figs. 5 and 6,-when once a button has been positioned, it is only necessary to push in that particular button and rotate the knob '51 until the disc 55 stops. The station represented by that button is then tuned in accurately. The rotation of the disc 55 is stopped when the shaft of the button 70 has been fitted in the notch of the pin 65. This is accomplished by the action of the spring 66 forcing the notch of the pin 65 over thebutton shaft when the arm 64 has brought the pin to the correct position.

The pin spring 66 is compressed when the pin is forced against it by the end of the button shaft. When a different station is desired ing broadcasting stations with a tuning mech-- anism embodying the above described invention is reduced topush button control when once adjusted to receive certain frequently desired stations. That is, any person unfamiliar with the usual method of oscillatory 'tuning of radio sets may move the knobs 20,

41 or 51 according to the modifidation being employed, to the stop or button representing the station designated by the indicator card and that station will be properly tuned in. It is then a simple-matter to regulate the volume of the receiver to meet the particular circumstances under which the reception is being had.

With the modification of Figs. 5 and 6 it is unnecessaryto pay any attention to stopping the tuning element at aparticular stop since this is performed automatically as described above. 'While this specification has described specific embodiments of the invention, it is to be understoodthat modifications may be made and that no limitations are intended other than those imposed by the scope of the appended claims.

What is claimed is: Y

' .1. In a station finder for a radio receiver having a variable tuning element, the combinationof, a control arm associated with said tuning element, adjustable stops for position-ing said control arm at predetermined .said 'armfor locking said arm to said stops. adapted to lock said adjusting means when locations, and means resiliently mounted on 2. In a station finder for a radio receiver having a rotatable operating shaft and a tuning condenser, the combination of'an adjusting arm for said condenser,said .condenser and arm being associated through said shaft, a plurality of adjustably positioned indicator stops adapted to cooperate with said arm, and resilient means for engaging said arm with said stops.

3. In a station finder for a radio receiver having a variable tuning element, the combination of a control arm for adjusting said element, said arm having a reciprocating elementmounted thereon, and a plurality of adjustable stops for engaging said reciprocating element in one position of said element, said stops being positioned so as to adjust said tuning element at predetermined locations when said arm is engaged With said stops. 1 4. In a tuning system for a radio receiver having a variable tuning element, the combination of a control arm for adjusting said element, a rotatable shaft associating said element'with said control arm, a plurality of adjustable stops adapted. to engage said arm in certain predetermined positions, independent means for'adjusting said element, and means for locking said control arm to said stops in said predetermined positions and releasing said arm therefrom to enable said tuning element to be operated by said independent means. i

5. A radio tuning system in accordance with'claim 4 in which said independent means comprises a friction wheel train'having a disc mounted on said shaft. 6. A radio tuning systemin accordance with claim 4 in which said locking and releasing means comprises a reciprocating element adapted to engage one of said stops when in a locking position.

7 Ina radio system having arotatable V shaft with a variable tuning element mounted thereon, the combination comprising,a control arm for adjusting said tuning element, said arm and element being associated through said rotatable shaft, a plurality of adjustable stop blocks for engaging said control arm, a second rotatable shaft, means for I controlling the rotation of said first shaft by rotation of said second shaft, and means for locking said first shaft in predetermined positions corresponding 'to the locations of said stop blocks,

8. A radiortuning system in accordance comprises a friction wheel train.

9. In a radio broadcast receiving s'et having a unitary tuning system and means for adjusting said tuning system, means including adjustable stop members adapted to be set at predetermined positions corresponding to exact broadcast station frequencies and with claim 7 in which said controlling means said'tuningsysteni is adjusted tosaid station, frequencies. 1 0. In a radio broadcast receiving set havmg a unitary tuning system, the combination compris1ng,.an escutcheon plate mounted on said set and having a circumferential path, an arm for adjusting said *tuning system, and means for engaging-said arm in adjustably. predetermined positions corresponding to "exm act broadcast station frequencies, said means comprising stop blocks fastened ''to (said escutcheon plate in said circumferential path.

1-1. In a radio broadcast receiving set ha'ving a unitary tuning system, the combina g tiomcomprising, an escutcheon plate mounted on said set and having a circumferential path a plurality of adjustable-stop blocks located in said path, an arm for controlling said tuning system, means for locking saidzcontrol an arm to said stop blocks to position said tun-ing system at exact broadcast station receiving frequencies, and auxiliary means for adjusting said tuning system independently of said control arm.

Ii 12. In a radio broadcast receiving set having a unitary tuning system mounted on a rotatable shaft, the combination of a rotatable member on said shaft, an element mounted on said member and adapted for limited- I. movement radially with respect thereto and adjustable means engaging said element for stopping said shaft at predetermined ositions corresponding to definite broa cast frequencies. I

13. The combination defined in claim 12 in which said engaging means comprises manually operated buttons for'locking saidrotatable member thereto when in an engaging position.

U 14. In a radio broadcast receiving set'h-aving a tuning system mounted on a rotatable shaft, the combination of a rotatable member. associated with said shaft, an element mounted on said member'and adapted for i limited movement radially with respect there to and a plurality of adjustable stops in ;predetermined POJSItiODS corresponding with definite broadcast frequencies adapted to engage said element said stops when in a for- Ufl ward-position loclringsaid shaft, and when in an outward sition releasingsaiel shaft. I

In witness w ereof, I hereunto subscribe my name this-22nd; day ofMarch, A.-D. 1929.

RICHARD -C. 

